Xapian discuss - Dec 2010 - Using a subclass of MatchSpy in Python bindings

Hi everyone,

I've searched the mail archives and I haven't been able to find a
solution to this. I want to subclass a MatchSpy in the Python bindings
and have Enquire use it. However, when I try to do so, I get a
TypeError raised. The following example illustrates this:
>>> import xapian
>>> database = xapian.Database(dbpath)
>>> class MyMatchSpy(xapian.MatchSpy):
...     def __init__(self):
...             pass
...     def __call__(self, *args, **kw):
...             print "called with", args, kw
...
>>> ms = MyMatchSpy()
>>> enquire = xapian.Enquire(database)
>>> enquire.add_matchspy(ms)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/dist-packages/xapian/__init__.py", line
6920, in _enquire_match_spy_add
    _enquire_add_matchspy_orig(self, decider)
TypeError: in method 'Enquire_add_matchspy', argument 2 of type
'Xapian::MatchSpy *'

Am I missing something obvious here, or is swig misbehaving? The above
works if ms is an instance of xapian.ValueCountMatchSpy, but I need to
implement something different to this.

I'm running the latest Xapian from Debian sid:
>>> xapian.version_string()
'1.2.3'

Thanks,

Munchkin

On Wed, Dec 01, 2010 at 01:18:40PM +0000, Doctor Munchkin
wrote:
> >>> class MyMatchSpy(xapian.MatchSpy):
> ...     def __init__(self):
> ...             pass
> ...     def __call__(self, *args, **kw):
> ...             print "called with", args, kw
> ...
> >>> ms = MyMatchSpy()
> >>> enquire = xapian.Enquire(database)
> >>> enquire.add_matchspy(ms)
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/python2.6/dist-packages/xapian/__init__.py",
line
> 6920, in _enquire_match_spy_add
>     _enquire_add_matchspy_orig(self, decider)
> TypeError: in method 'Enquire_add_matchspy', argument 2 of type
> 'Xapian::MatchSpy *'
> 
> Am I missing something obvious here, or is swig misbehaving? The above
> works if ms is an instance of xapian.ValueCountMatchSpy, but I need to
> implement something different to this.
I think you need to call the base class constructor in your constructor:

    def __init__(self):
        xapian.MatchSpy.__init__(self)

Cheers,
    Olly

Hi,

http://ccdevnet.org/~fuzzie/matchspy.txt fixes this (not actually tested
against trunk, but maybe it is useful for someone).

- Alyssa